OK, let me just tell you right off the bat - if you can't find an attorney to take your case on a contingency basis, it's because either you have a VERY weak case, OR, your case isn't worth enough money for his 40% to make it worth his while.
And a few other things . . .regardless of insurance, you are ALWAYS responsible to your medical provider, for services you contracted, whether the insurance pays or not. Your provider is going to win this lawsuit. They'll garnish your wages, if you ever get a job again, and attach your assets, until the debt plus court costs plus interest is paid off, or until you file bankruptcy.
Without having any details on the condition or the preexistance, I'd just like to point out, that many people are under the mistaken impression that "preEXISTING" and "preDIAGNOSED" are the same thing. They aren't. If your condition existed - whether or not it was diagnosed officially - before you purchased the insurance, it IS preexisting.
The way to AVOID preexisting condition problems, is to NOT go without health insurance. If you have had health insurance for 10 years before buying this policy, it wouldn't have been a problem. But, many, many people WAIT until AFTER they have symptoms to buy the insurance, and lie about not having symptoms, and try to pretend that it's not preexisting. Then, when they get caught (because the doctor says the condition took at least six months to develop, or whatever), and the insurance company denies the claim, they get all bent.
Fees vary pretty widely. Lawyers should be very up front about their fee structure before beginning to represent you.
Typically, there are a few kinds of fee structures, Hourly fees, Hourly fees with retainers, Contingency fees, and Flat fees.
Hourly fees can run between around $125-300 depending on the experience level of the lawyer or the firm he or she works for.
Retainers are large advance sums paid to a lawyer to guarantee his availability. When work is needed hourly fees are deducted from the retainer. Typical retainers are about $3000.
Contingency fees are payments from whatever a lawyer is able to recover for you in a lawsuit. Typical amounts are between 20-30%.
Flat fees are per item fees, and can vary depending on experience level and complexity of the project.
Sometimes lawyers will charge more for specialized work, such as actually conducting a trial (i.e., 20% contingency fee in settlement, 30% in jury verdict). Also keep in mind expenses such as attorney travel will also be added to your fees.
You can find local attorney listings by contacting your county or state bar association, which should have a website and hotline as well as looking at organizations like findlaw.